The atomic mass of a metal M is 56. Calculate the empirical formula of its oxide containing 70 % metal.

Answer

`M_(2)O_(3)`

Explanation

Empirical formula may be calculated as :
`{:("Element","Percentage","Atomic mass","Gram atoms (Moles)","Atomic ratio (Molar ratio)","Simplest whole no. ratio"),("M",70.0,56,(70.0)/(56)=1.25,(1.25)/(1.25)=1.0,2),("O",30.0,16,(30.0)/(16)=1.88,(1.88)/(1.25)=1.5,3):}`
Empirical formula of metal oxide `= M_(2)O_(3)`.